<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
	<meta name="viewport" content="initial-scale=1.0, maximum-scale=0.5, user-scalable=no" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>模拟聊天</title>
<style>
*{ margin:0; padding:0}
input{ vertical-align:middle}
.main{ width:100%; margin:10px auto 0;}
.dialog{height:1000px; border:1px solid #ccc; overflow:auto}
.talkArea{ margin-top:20px;}
textarea{ width:100%; height:100px; resize:none; border:1px solid #ccc}
p { overflow:hidden; margin-bottom:20px; padding:10px}
p span{ padding:10px; background:#ddd;}
button{ height:40px; width:100px;}
.fl{float:left;}
.fr{ float:right;}
</style>
</head>

<body>
<div class="main">
    <div id="dialog" class="dialog">
    	<div id="cont" class="cont">
        	<p><span class="fl">hi</span></p>
        	<p><span class="fl">我是你的专属客服"善善"</span></p>
            <p><span class="fl">请问有什么可以帮助你?</span></p>
        </div>
    </div>

    <div class="talkArea">
        <textarea id="textArea"></textarea>
        <p style="text-align:right;">
        	<label style="font-size:12px; color:#999"><input id="checkbox" type="checkbox" /> 回车直接发言</label>
            <button id="btn" type="button" disabled>发言</button>
        </p>
    </div>
</div>

</body>
<script>

		var arr=['hi',"18","我是帅哥","谢谢","你说啥??"];

		var dialog=document.getElementById('dialog');
		var cont=document.getElementById('cont');
		var oBtn=document.getElementById('btn');
		var textArea=document.getElementById('textArea');
		var chkBox=document.getElementById('checkbox');

		var txt="";//保存输入内容


		//点击发送----------------------------------------------
		oBtn.onclick=send;

		function send(){
			cont.innerHTML+='<p><span class="fr">'+textArea.value+'</span></p>';

			dialog.scrollTop=dialog.scrollHeight-dialog.clientHeight;//设置滚动条在最底部

			oBtn.disabled=true;

			txt=textArea.value;

			textArea.value="";

			//textArea.focus();

			//2秒后自动回话
			setTimeout(function(){
				switch(txt){
					case "你好":
					cont.innerHTML+='<p><span class="fl">'+arr[0]+'</span></p>';
					break;
					case "你多大":
					cont.innerHTML+='<p><span class="fl">'+arr[1]+'</span></p>';
					break;
					case "你是男生女生":
					cont.innerHTML+='<p><span class="fl">'+arr[2]+'</span></p>';
					break;
					case "你真漂亮":
					cont.innerHTML+='<p><span class="fl">'+arr[3]+'</span></p>';
					break;
					default:
					cont.innerHTML+='<p><span class="fl">'+arr[4]+'</span></p>';
				}
				dialog.scrollTop=dialog.scrollHeight-dialog.clientHeight;
			},2000);
		};


		//输入文本控制按钮状态---------------------------------------------
		textArea.onkeyup=function(){
			oBtn.disabled=this.value!="" ? false:true;
		};

		//控制回车直接发送----------------------------------------
		textArea.onkeydown=function(ev){
			ev=ev||event;
			if(chkBox.checked && ev.keyCode==13){
				send();
				return false; //无法再进行输入(防止textarea内部回车)
			};
		};


    </script>
</html>